UBUNTU: SAUCE: make snap-pkg support

BugLink: http://bugs.launchpad.net/bugs/1700747

This patch integrates snapcraft in the kbuild environment of the Linux kernel.

To use it:

make defconfig
make snap-pkg

or in case of cross-compilation (e.g. arm):

export ARCH=arm; export CROSS_COMPILE=arm-linux-gnueabihf-
make defconfig
make snap-pkg

The resulting kernel snap will be generated in $(objtree)/snap
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>
Acked-by: Stefan Bader <stefan.bader@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>

.gitignore

@@ -56,6 +56,11 @@ Module.symvers
 #
 #/debian/
 
+#
+# Snap directory (make snap-pkg)
+#
+/snap/
+
 #
 # tar directory (make tar*-pkg)
 #

scripts/package/Makefile

@@ -99,6 +99,19 @@ bindeb-pkg: FORCE
 
 clean-dirs += $(objtree)/debian/
 
+# snap-pkg
+# ---------------------------------------------------------------------------
+snap-pkg: FORCE
+	rm -rf $(objtree)/snap
+	mkdir $(objtree)/snap
+	sed "s@KERNELRELEASE@$(KERNELRELEASE)@; \
+		s@SRCTREE@$(shell realpath $(srctree))@" \
+		$(srctree)/scripts/package/snapcraft.template > \
+		$(objtree)/snap/snapcraft.yaml
+	cd $(objtree)/snap && \
+	snapcraft --target-arch=$(UTS_MACHINE)
+
+clean-dirs += $(objtree)/snap/
 
 # tarball targets
 # ---------------------------------------------------------------------------

scripts/package/snapcraft.template

+name: kernel
+version: KERNELRELEASE
+summary: Linux kernel
+description: The upstream Linux kernel
+grade: stable
+confinement: strict
+type: kernel
+
+parts:
+  kernel:
+    plugin: kernel
+    source: SRCTREE
+    source-type: git
+    kconfigfile: SRCTREE/.config